Original paper
A revision of Mastodonsaurus from the Anisian of Germany, and the evolutionary history of mastodonsaurid temnospondyls
Schoch, Rainer R.; Milner, Andrew; Witzmann, Florian; Mujal, Eudald
Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen Band 309 Heft 2 (2023), p. 123 - 140
61 references
published: Aug 31, 2023
manuscript accepted: Jul 25, 2023
manuscript received: Jun 11, 2023
ArtNo. ESP155030902003, Price: 29.00 €
Abstract
Reexamination of Mastodonsaurus (Heptasaurus) cappelensis, a three-metre long capitosaur temnospondyl from the Upper Buntsandstein (Anisian, Middle Triassic), reveals formerly poorly known or unrecognized features of this earliest mastodonsaurid temnospondyl. M. cappelensis differs from the stratigraphically younger type species M. giganteus in the following characters: tip of snout wider, orbits narrower and more oval shaped, frontal shorter and postorbital and squamosal smaller. In the postcranium, the intercentra are massive but dorsally not closed, whereas the humerus is longer and more gracile and the ilium more robust with an expanded dorsal end. The evolution of the Mastodonsaurus lineage involved the acquisition of very large tusks and an extension in the attachment areas of jaw opening and closing musculature. These changes probably enabled M. giganteus to extend the range of prey, assuming the position of a top predator in the rich lacustrine ecosystems of the Lower Keuper.
Keywords
Capitosauria • phylogeny • stratigraphy • Temnospondyli • Triassic